3-Methoxycarbonylmethyl-2-t-butoxycarbonyl-2-(2-pentynyl)-cyclopentanol → 2-Tert-butoxycarbonyl-3-methoxycarbonylmethyl-2-(cis-2-pentenyl)-cyclopentanol

Participants

Reaction Steps

A 1.4 g quantity of 3-methoxycarbonylmethyl-2-methoxycarbonyl-2-(2-pentynyl)-cyclopentanol (compound (1-a)) and 2.2 g of Lindlar catalyst are dissolved in a mixture of 50 ml of n-hexane and 5 ml of acetone. The starting compound is thus reduced at room temperature and atmospheric pressure with use of hydrogen gas. The reaction is completed when the solution has absorbed the theoretical amount of the gas, whereupon the catalyst is filtered off. The filtrate is concentrated in vacuo, and the residue dissolved in benzene-ethyl acetate and purified with a silica gel column. The product is distilled in a vacuum, giving 2-methoxycarbonyl-3-methoxycarbonylmethyl-2-(cis-2-pentenyl)-cyclopentanol (compound (1-b), R1 =R2 =CH3) in a yield of 87%, b.p. 74°-78° C./0.01 mm Hg.

Provenance & Evidence